Poor man's flexible input device: keyboard sketched on paper and a touchscreen

A hybrid of old and new technology: A resistive touch screen over a sketched / printed 'keyboard' layout provides flexible input options. Getting rid of physical buttons and have unlimited entry options - that's what this is all about.

Here is my universal Espruino (PICO) keyboard. A few modules including a configuration module make a simple calculator entry.

2 Attachments

Here part of the code with input/output example:

// touchKeyPadCalc2.js
// (c)20181004_aO
var kvs = "789CA456*/123+-00.==" // key values grid linear
  , tkp = new (require("TouchKeyPad"))(
     0,141,24,103,5,4,kvs) // grid area, cols, rows
  , trd = new (require("TouchRD"))(B1,A5,A6,A7
    ,function(x,y,t) { if (!t.t) // on un-touch:
      console.log(t.x,t.y,tkp.key(t.x,t.y),tkp.k,tkp.r,tkp.c); }
    ,require("TSRD26_142x104_cfg")
    );

The actual calculator is still on the list (suggestions are welcome) as well as attaching any kind of display. Output of input shows in console so far (: - Touching 8 2 . 5 x 3 = produces this output (formatted and 'headed' posthume for legibility):

`
touched lup lin -grid-
@       key key row col
  x   y val idx idx idx
--- --- --- --- --- ---
 38  36  8    1   0   1
 39  76  2   11   2   1
 64 100  .   17   3   2
 40  58  5    6   1   1
 96  57  *    8   1   3
 69  75  3   12   2   2
108  96  =   18   3   3
`

PS: Configured screen resolution is 142 W x 104 H spots (pixels), 0/0 is at left (x) top (y). Reasons for chosen resolution will be subject of another conversation.

...more to come...

Wow, I like that touch screen

https://www.smitacn.com/resistive-touch-screen-digitizer-glass-054005.html?gclid=EAIaIQobChMIpNbK4Jb33QIV1eWaCh0tWwaiEAkYAyABEgJblfD_BwE

What about this one? Is it similar to the one you use ?

Yes, I got mine from https://www.buydisplay.com/ - https://www.ebay.com/usr/buydisplay - directly - the shop(s) of the manufacturer EastRising Technology Co., Ltd. I guess, because the manufacturer Web site has no other indication. I buy always 2+, because they are somewhat fragile... broke my first when 'gently pushing' it into its location in 3d printed frame,... the gently was obviously not so gentle and a corner broke off... small, but of course exactly the one with the trace going around the corner opposite of the film connector, so I lost the Upper (in portrait) feed and sense line...

buydisplay is the source of (almost) all my displays, since I do not need the fruity, access easing surroundings (from adaFruit... I though admit that my first add-ons when getting started with Original Espruino board came from adafruit: display w/ resistive touchscreen (no touch screen controller), wifi CC3000 board, and possibly M6 uBlox GPS).

Looks great! Do you have links to your touchRD and touchKey modules?

Getting the modules ready.

Modules are now on https://www.espruino.com/modules:

• TouchRD - Resistive Touchscreen Directly connected to Espruino
  
  • Documentation - TouchRD - espruino.com/TouchRD
    
  • Code - [TouchRD - ]espruino.com/modules/TouchRD.js](https://www.espruino.com/modules/TouchRD.js)
    
• TouchKeyPad - Mapping touch position in grid to a key value:
  
  • Documentation - TouchKeyPad - espruino.com/TouchKeyPad
    
  • Code - TouchKeyPadRD - espruino.com/modules/TouchKeyPad.js ]
    
    

TouchRD Documentation includes generic code for calibration for Portrait and Landscape use.

The configuration(s) as used in post #1 were created with the generic calibration code and then copied into the modules folder of the sandbox in the Espruino IDE:

// TSRD26_104x132_cfg.js (c) 20181003_allObjects
// BuyDisplay.com 2.6" Resistive Touch Screen
// Portrait configuration 104 W x 142 H
// for TouchRD.js module
exports = 
  { X: 104
  , Y: 142
  , xt: 0.1117
  , yt: 0.0854
  , xc: 0.5067
  , yc: 0.4876
  , xd: 0.00736
  , yd: 0.00553
  };

// TSRD26_142x104_cfg.js - 20181003_allObjects
// BuyDisplay.com 2.6" Resistive Touch Screen
// Landscape configuration 142 W x 104 H
// for TouchRD.js module
exports = 
  { X: 142
  , Y: 104
  , xm: 5
  , ym: 5
  , xt: 0.0822
  , yt: 0.0966
  , xc: 0.4694
  , yc: 0.4960
  , xd: 0.00534
  , yd: 0.00744
  };